Answer:
If 30 houses cost 1.7 billion, 300 houses cost 17 billion
Explanation:
If you were to make it an equation you would make it
30 = 1.7
Now we were told the 30 would be made 300 so its obvious you multiplied by 10 and whatever you did to one side you do to the other so its
30 x 10 = 1.7 x 10 is 300 = 17
your answer is 17 billion